A variety of applications exist for wideband, multi-mode, multi-function apertures for electronic warfare (e.g., threat detection, threat avoidance, suppression of enemy air defenses, surveillance, and reconnaissance). In many of these applications the objectives are to reduce cost and weight for adaptive, wideband conformal phased arrays that are integrated into potential unmanned aerospace platforms. These arrays often have multiple polarization elements and perform over a wide frequency range.
For example, high-altitude airships such as gas filled dirigibles or blimps have shapes adapted for maximizing their aerodynamic performance such as lift, maneuverability and stationary or forward movements. The airship's skin materials and craft shape often challenge equipment designers in their efforts to effectively mount information gathering instrumentation, such as radar systems.
High-altitude airships also generally have challenged load and weight capabilities, which play heavily in the design of the equipment (such as lightweight phased array radar antennas) they can feasibly transport. Currently, X-Band band tile subarrays having mass density of 5 Kilograms per square meter (5 Kg/m2) have been utilized. Aircraft efficiency can substantially benefit by reductions in the mass density of such arrays. Also, due to power limitations in airships the prime power density consumption should be on the order of magnitude of a few watts per square meter. Still further, an array size in the class of high-altitude airships can be several thousand square meters. Scalability from a common building block is extremely useful for manufacturing, installation and service. Alternative approaches to the design of active electronically steered phased arrays are needed.